The goal of this research is to employ a recently characterized HIV-2287 model of vertical transmission and rapid pathogenicity in neonatal macaques (M. nemestrina) to determine whether an effective and safe immunogen can be developed for prophylactic or therapeutic use in preventing, aborting, or down modulating prenatal HIV infection and progression. The investigators will apply previous work concerning liposome carriers to prepare HIV-2287 Env formulated in macrophage-tropic muramyl-tripepetide phosphatidyl-ethanolamine (MTP-PE) liposomes. Effects of antigen carrier immunization will be monitored by an extensive array of virus-specific immunological parameters over an eight month period. Neonatal macques will be provided from a concurrent grant studying factors in HIV-2287 transmission from mother to offspring. Preliminary data concerning HIV- 2287 liposome antigen carrier preparations will be obtained in a small animals (mice, guinea pigs) with the intent of preselecting immunogenic HIV 2287 candidate vaccine preparations for use in the macaques studies.